Debug Mode
At the Title screen,hold down Triangle+Square+X and start a new game.You will now get 100% completion.During game hold Select and hit Start.Lots of stars will start falling, collect them all until your egg buddies are full-grown or stock up on lives.Then hold Select and press Start one more time to clear the stage.Also if you hold down Square in the map screen, Hermie will run across the map.

Power Ups
At the Title Screen, hold Triangle & Square & Cross and start a new game.

During the game press and hold Select and press Start. Stars will fall which can be used to Level-Up your egg-buddies until they are fully grown.

Hold Select and press Start to clear the stage.